【聯合報╱By STANLEY REED╱陳世欽譯】
Dutch Earthquakes Unsettle a European Energy Source
LOPPERSUM, the Netherlands — Europe’s largest source of natural gas, known as the Groningen gas field , has long powered the economy of the Netherlands and has been a reliable supply of gas for Northern Europe.
But a half-century of extraction has reduced the field’s natural pressure , and seismic shifts from geological settling have set off increasingly frequent earthquakes — more than 120 last year, and at least 40 this year. Though most of the tremors have been small, and resulted in no reported deaths or serious injuries, they have caused widespread damage to buildings, endangered nearby dikes and angered residents.
Now the Dutch government is demanding that the field’s operator, a joint venture of Royal Dutch Shell and Exxon Mobil, curtail production, making the Groningen field much more than a local worry. The field accounts for about one-third of the natural gas produced in the European Union. Any reduction in output might be especially hard for the European economy to bear now that tension in Ukraine is making the receipt of gas from Russia uncertain and Moscow is pivoting its energy attention toward China.
People living atop the Groningen field are trying to cope with the on-the-ground consequences. Nienke Pastoor and her husband, Jaap, spent years restoring a 110-year-old farmhouse. But an earthquake in 2012 left cracks in the walls and inflicted more serious structural damage to the home of Mr. Pastoor’s parents across the road, causing them to suspend plans to swap homes to be closer to their farmland. “I have four children,” Mrs. Pastoor said. “If they go to sleep and it starts to shake, what is going to happen?”
The geological problems posed even by the traditional drilling techniques used here could provide fodder for critics of hydraulic fracturing, or fracking, which is being used elsewhere to extract gas from shale rock and has caused quakes in Britain.
As part of a three-year test, the Dutch government has ordered the joint venture that operates the Groningen field, Nederlandse Aardolie Maatschappij, or NAM, to cut production by about 20 percent from last year’s level. It has also demanded other corrective measures, including reinvesting some profits into the local economy.
About 150,000 people live above the field, which occupies about 900 square kilometers. The field contributes as much as 12 billion euros, or $16.4 billion, to the national government each year, or more than 4 percent of its revenue. Shell and Exxon are thought to split around ?1 billion a year in earnings from the field.
Jan Willem Jacobs, NAM’s project director for the field, said the company accepted responsibility for the earthquakes and for fixing the damage they caused.
Many residents remain skeptical that anything will change .
“NAM has spoiled trust over the last 20 to 30 years, ” said Jacques Wallage, a former member of the Dutch cabinet and a former mayor of Groningen .
For much of Groningen’s first 50 years, the field was so prolific that it required little additional drilling after the initial development.
The 20 or so production centers scattered about the countryside quietly did their work , sending gas into the national pipeline network and points beyond. Then came the earthquakes, beginning in the early 1990s, with increasing frequency and intensity.
In August 2012, a quake with a magnitude of 3.6, the largest so far, frightened residents and caused widespread damage .
“At that time, the region awoke to the real danger for this area,” said Albert Rodenboog, the mayor of Loppersum, who has helped coordinate efforts urging the government and NAM to take action.
The gas is trapped in porous sandstone deep beneath the ground. When the fuel flows to the surface, the rock contracts like a squeezed sponge.
In some places in the Groningen area, this contraction has caused the surface of what is already a low-lying area drained by numerous canals to sink as much as 35 centimeters. NAM has invested heavily in new water pumping stations .
NAM ’s new production ceiling, at 42.5 billion cubic meters, would still be higher than the 38 billion cubic meters a year that Russia recently agreed to supply to China.
T he Dutch government also is placing Groningen’s most accessible gas further out of reach. It has ordered the company to sharply curtail production at five sites in the Loppersum area, the epicenter of the quakes.
The company and various authorities have also agreed on a five-year, ?1.2 billion package to repair and reinforce homes and other buildings that have sustained damage.
The test is one that many say Groningen cannot afford to fail.
“If there is one casualty, everything is different here,” said Daniella Blanken of the citizens group Groninger Bodem Beweging, or Groningen Earth Movement. “One casualty is going to put the region on fire.”
中譯
格洛寧根天然氣田是歐洲最大的天然氣產地，多年來一直提供驅動荷蘭經濟的能源，而且穩定供應北歐。
然而長達半世紀的開採已使它的天然壓力下降，地質沉澱產生的地震變化導致地震更頻繁，去年超過120次，今年至少已有40次。雖然多數地震規模不大，亦未聞有人死亡或重傷，卻使建築物廣泛受損，同時危及附近的堤防，引起居民強烈不滿。
荷蘭政府已經要求負責經營的皇家荷蘭殼牌與埃克森美孚石油公司合資企業減產。這導致格洛寧根天然氣田不只引起當地人的憂慮。它的天然氣產量約占歐盟的1/3。在烏克蘭的緊張局勢造成俄國天然氣供應不確定，俄國並將能源供應焦點轉向中國大陸之際，減產可能對歐洲經濟造成尤其嚴重的衝擊。
住在格洛寧根天然氣田上的民眾正在設法應付地面所受影響。
妮安姬‧帕斯托與丈夫傑普以數年時間整修一棟已有110年歷史的農舍，然而2012年的一次地震使農舍的牆壁出現裂痕，同時使帕斯托父母在對街的住處受到嚴重的結構性破壞，迫使他們暫緩互換房屋以便更接近自家農地的計畫。
妮安姬說：「我有四個孩子。如果他們睡覺時發生地震，會怎麼樣？」
傳統開採技術在這裡造成地質問題，可能使水裂開採法的批評者更有反對的理由。有些其他地區以水裂法開採頁岩
的天然氣，曾在英國引起地震。
荷蘭政府推出三年實驗計畫，要求經營格洛寧根天然氣田的NAM公司將今年的產量降至去年的4/5，同時採取多項補救措施，包括將部分利潤轉投資於當地經濟。大約15萬人住在這片約900平方公里的天然氣田上。
天然氣田每年為荷蘭政府帶來120億歐元（約164億美元）的收入，占歲入的4%以上。估計殼牌與埃克森公司每年可平分10億美元利潤。
NAM的格洛寧根天然氣田計畫經理雅各斯說，該公司承擔地震的責任與損害修補的開銷。
不過許多居民還是認為，現狀不太可能改變。曾經入閣並擔任過格洛寧根市長的華勒吉說：「過去二、三十年間，NAM糟蹋了人們對它的信任。」
在格洛寧根天然氣田運作前50年的許多歲月，蘊藏量大到在最初開發規模外，幾乎不需再做額外鑽採。約20個生產中心散布於鄉間，靜靜運作，把天然氣源源送到全國的管線系統與國外。
後來，在1990年代初地震出現了。越來越多，也越來越大。2012年8月，一場至今最大的芮氏規模3.6地震嚇壞當地居民，同時造成廣泛損壞。
洛普桑市長羅登柏格曾經協調民眾督促荷蘭政府與NAM公司採取行動。他說：「當時，整個區域驚覺本地區面臨的真實威脅。」
天然氣鎖在地底深處的多孔沙岩內。天然氣流到地面時，岩石有如受到擠壓的海綿般收縮。
在格洛寧根地區的部分地方，這種收縮導致原已因為許多運河吸水而形成的低海拔地帶下沉，最多達35公分。NAM挹注重資興建新的抽水站。
NAM的生產上限已降為每年425億立方公尺，但仍高於俄國最近同意供應中國大陸的380億立方公尺。
荷蘭政府正在使格洛寧根最容易取得的天然氣更難以取得，要求在地震震央洛普桑地區的五個地點大幅減產。
該公司與各有關當局已決定以五年時間投入12億歐元，整修並強化在地震中受損的民宅與其他建築。
許多人表示，格洛寧根非通過這個考驗不可，否則後果不堪設想。
公民團體「格洛寧根地球運動」的布蘭肯說：「只要有一人死傷，一切就會完全不同。一人死傷就會使整個區域變成一片火海。」
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